388 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



part in the anterior part of the hypocone. The dorsal surface is more convex than the ventral, 

 thus placing both apices slightly ventrad of the median frontal plane of the body. The hypocone 

 exceeds the epieone in size. The epicone is broadly rounded, less than a hemisphere, with a 

 length from the proximal and distal ends of the girdle of 0.19 and 0.82 respectively of the total 

 length of the body. On the dorsal and right sides of the body the basal portion forms a flaring 

 border to the girdle, with less prominence elsewhere. The hypocone is conical in shape, with 

 an angle of about 45°. It is narrower distally than the epieone with rounded antapex. An- 

 teriorly it forms a shelflike border to the girdle. 



The proximal and distal ends of the girdle join the sulcus at a distance from the apex of 

 0.19 and 0.82 respectively of the total length of the body. It sweeps around the body in a 

 descending left spiral of 1.5 turns with a displacement of 0.82 transdiameter. The first trans- 

 diameter of its course is nearly transverse beyond which it turns posteriorly at a gradually 

 steepening angle which becomes about 35° for the last 0.5 of its course. The furrow has a 

 width of about 0.08 transdiameter, slightly narrower anteriorly, and is deeply impressed with 

 borders raised somewhat above the surrounding surface. 



The sulcus invades the epieone to within a short distance of the apex. After passing the 

 proximal end of the girdle it is deflected to the left, and continues posteriorly in a spiral course 

 to near the antapex, its torsion about 0.5 turn. It is rather shallow with smooth borders. The 

 anterior and posterior flagellar pores open at the anterior and posterior junctions respectively 

 of the girdle and sulcus. 



The nucleus is a large ellipsoidal body, filled with fine, parallel, moniliform chromatin strands 

 which follow its long axis. It is located in the anterocentral part of the body. Its major and 

 minor axes are 0.46 and 0.31 tran.sdiameter respectively. 



The cytoplasm is very clear and transparent, and contains numerous blue-green oil globules 

 of varying sizes. A small, club-shaped pusule opens into the posterior flagellar pore, a larger, 

 sacklike one with a long, slender, curved diverticulum extending dorsad, opening into the 

 anterior pore. The surface is striate with longitudinal blue-green lines extending from the 

 girdle to the apices. The number of lines on the epicone exceeds the number on the hypocone 

 by about 0.2. The general color of the organism is yellowish green diffused throughout the 

 cytoplasm. 



DiMEXsioxs. — Length, 60/^ ; transdiameter, ilj^ ; axes of niieleus, 19/^ and 13/^. 



OcCTJRRExcE. — Two individuals were taken Augaist 10, 1917, with a Xo. 25 

 silk net, 1 mile off La Jolla, California, in a lianl 50 meters to the surface, in 

 a surface temperature of about 21° C 



Co:mp.vkisoxs. — In the type of spiral the girdle of C. vohdiun resembles 

 somewhat that of C. conspiratum (fig. GG, 10), being slightly more regidar in 

 its course. In shape of body and apices it is close to C. scintiUans sp. nov. (fig. 

 GG, 11), but has striae on its surface. It belongs to the C. mi)iiatum group of 

 the subgenus Cocldodinium, and shares with C. miniatum the distinction of a 

 Gyrodiniiun type of striate surface. 



